Re: [PATCH RFC 0/9] Launching processes with io_uring

[Pavel Begunkov <asml.silence@gmail.com>]

On 1/23/25 00:31, Pavel Begunkov wrote:
> On 1/22/25 23:49, Askar Safin wrote:
>>   ---- On Sun, 19 Jan 2025 07:03:51 +0400  Pavel Begunkov  wrote ---
>>   > I also wonder, if copying the page table is a performance problem, why
>>   > CLONE_VM + exec is not an option?
>>
>> Do you mean CLONE_VFORK? Anyway, CLONE_VM surprisingly turns out
> 
> No, vfork is troublesome. What I mean is a task that shares
> the page table, or in other words a vfork that doesn't block
> and has a dedicated stack.
> 
>> to be a good solution. So thank you!
>>
>> There is a bug in libc or in Linux: https://sourceware.org/bugzilla/show_bug.cgi?id=32565 .
>>
>> I suspect this is actually a Linux bug.
>>
>> After receiving your letter I decided to try CLONE_VM. And it works!
>> There is no bug in CLONE_VM version! You can see more details here:
>> https://www.openwall.com/lists/musl/2025/01/22/1
> 
> I haven't looked at the bug, but IIUC fundamentally posix_spawn()
> does the same thing, and if so it's likely that any problem you
> have with posix_spawn() could be triggered for your hand crafted
> version.

Seems I was wrong, posix_spawn(3) mentions it uses CLONE_VFORK.

-- 
Pavel Begunkov